The effect of the important chemical constituents in the Handford nuclear waste simulant on
the anodic behavior of carbon steel was studied. Specifically, the effect of pH, nitrite
concentration, nitrite/nitrate concentration ratios, total organic carbon and the chloride
concentration on the open circuit potential, pitting potential and repassivation potential was
evaluated. It was found that pH adjusting, although capable of returning the tank chemistry
back to specification, did not significantly reduce the corrosivity of the stimulant compared to
the present condition. Nitrite was found to be a potent inhibitor for carbon steel. A critical
concentration of approximately 1.2M appeared to be beneficial to increase the difference of
repassivation potential and open circuit potential considerably and thus prevent pitting
corrosion from occurring. No further benefit was gained when increasing nitrite concentration
to a higher level. The organic compounds were found to be weak inhibitors in the absence of
nitrite and the change of chloride from 0.05M to 0.2M did not alter the anodic behavior
dramatically.